Semiconductor device, solid-state imaging device and electronic apparatus

ABSTRACT

A semiconductor device including a first semiconductor section including a first wiring layer at one side thereof, the first semiconductor section further including a photodiode, a second semiconductor section including a second wiring layer at one side thereof, the first and second semiconductor sections being secured together, a third semiconductor section including a third wiring layer at one side thereof, the second and the third semiconductor sections being secured together such the first semiconductor section, second semiconductor section, and the third semiconductor section are stacked together, and a first conductive material electrically connecting at least two of (i) the first wiring layer, (ii) the second wiring layer, and (iii) the third wiring layer such that the electrically connected wiring layers are in electrical communication.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/852,468, filed Dec. 22, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/403,154, filed Jan. 10, 2017, now U.S. Pat. No.9,917,131, which is a continuation of U.S. patent application Ser. No.15/087,894, filed Mar.31, 2016, now U.S. Pat. No. 9,570,499, which is acontinuation of U.S. patent application Ser. No. 14/434,288, filed Apr.8, 2015, now U.S. Pat. No. 9,431,450, which is a national stageapplication under 35 U.S.C. 371 and claims the benefit of PCTApplication No. PCT/JP2013/006055, filed Oct. 10, 2013, which claimspriority to Japanese Patent Application Nos. JP 2012-230805 and JP2013-089580, filed in the Japan Patent Office on Oct. 18, 2012, and Apr.22, 2013, respectively, the entire disclosures of which are herebyincorporated herein by reference.

TECHNICAL FIELD

The present technology relates to a solid-state imaging device, andparticularly to a solid-state imaging device capable of easily providinga high-quality stacked image sensor.

BACKGROUND ART

As solid-state imaging devices, there is an amplification typesolid-state imaging device represented by a MOS type image sensor suchas a complementary metal oxide semiconductor (CMOS). In addition, thereis a charge transfer type solid-state imaging device represented by acharge coupled device (CCD) image sensor.

These solid-state imaging devices are frequently used in digital stillcameras, digital video cameras, and the like. In recent years, assolid-state imaging devices have been mounted in mobile apparatuses,such as mobile phones and personal digital assistants (PDAs) withcameras, a MOS type image sensor has been frequently used from theviewpoint of having a low power supply voltage, low power consumption,and the like.

The MOS type solid-state imaging device includes a pixel array (pixelregion) in which a plurality of unit pixels are arranged in atwo-dimensional array form and a peripheral circuit region, and each ofthe unit pixels includes a photo diode which is a photoelectricconversion portion and a plurality of pixel transistors. A plurality ofpixel transistors are formed of MOS transistors, and generally comprisethree transistors including a transfer transistor, a reset transistor,an amplification transistor, or four transistors additionally includinga selection transistor.

In addition, in the above-described solid-state imaging device, astacked structure has been proposed in which a plurality ofsemiconductor substrates having different functions are stacked in anoverlapping manner and are electrically connected to each other.

In the stacked structure, since each circuit can be formed optimally soas to correspond to the function of each semiconductor substrate, it ispossible to easily realize high performance of a device.

For example, it is possible to manufacture a high performancesolid-state imaging device by optimally forming a sensor circuit and alogical circuit so as to correspond to respective functions of asemiconductor substrate including the sensor circuit and a semiconductorsubstrate including the logical circuit in which a circuit processingsignal is provided. At this time, through electrodes are provided insubstrates of the semiconductor substrates, and thereby the plurality ofsemiconductor substrates are electrically connected to each other.

However, if a semiconductor device is formed by connecting differentsubstrates to each other by using a connection conductor whichpenetrates through a substrate, it is necessary to form a connectionhole while maintaining insulation in the deep substrate, and thus apractical use is difficult from the viewpoint of economic costs of amanufacturing process which is necessary in creating the connection holeand embedding the connection conductor.

On the other hand, for example, if a small contact hole of about 1micrometer is to be formed, it is necessary to thin an upper substrateto the utmost limit. In this case, complex steps such as, attaching theupper substrate to a support substrate before being thinned and anincrease in costs may result. In addition, in order to embed aconnection conductor in a connection hole with a high aspect ratio, aCVD film having a good coatability property, such as tungsten (W), isnecessarily used as a connection conductor, and thus materials to beused as a connection conductor may be limited.

Therefore, a manufacturing method of a semiconductor device such as asolid-state imaging device has been proposed which achieves a highperformance by sufficiently exhibiting each performance, massproductivity, and a reduction in costs (for example, refer to PTL 1).

PTL 1 has proposed a stacked structure in which a support substrate of arear surface type image sensor is stacked as a logical circuit, and aplurality of connection contacts are provided from the top by using athinning step of the image sensor.

CITATION LIST Patent Literature

[PTL 1]

Japanese Unexamined Patent Application Publication No. 2010-245506

SUMMARY OF INVENTION Technical Problem

It is desirable to easily provide a high-quality stacked image sensor.

Solution to Problem

In accordance with at least one embodiment of the present invention, asemiconductor device is provided, the semiconductor device comprising afirst semiconductor section including a first wiring layer at one sidethereof, the first semiconductor section further including a photodiode,a second semiconductor section including a second wiring layer at oneside thereof, the first and second semiconductor sections being securedtogether, a third semiconductor section including a third wiring layerat one side thereof, the second and the third semiconductor sectionsbeing secured together such the first semiconductor section, secondsemiconductor section, and the third semiconductor section are stackedtogether, and a first conductive material electrically connecting atleast two of (i) the first wiring layer, (ii) the second wiring layer,and (iii) the third wiring layer such that the electrically connectedwiring layers are in electrical communication.

In accordance with at least one embodiment of the present invention, abackside illumination type solid-state imaging device is provided, thesolid-state imaging device comprising a first semiconductor sectionincluding a first wiring layer at one side thereof, the firstsemiconductor section further including a circuit region and a pixelregion, a second semiconductor section including a second wiring layerat one side thereof, the first and second semiconductor sections beingsecured together, a third semiconductor section including a third wiringlayer at one side thereof, the second and the third semiconductorsections being secured together such the first semiconductor section,second semiconductor section, and the third semiconductor section arestacked together, and a first conductive material electricallyconnecting at least two of (i) the first wiring layer, (ii) the secondwiring layer, and (iii) the third wiring layer such that theelectrically connected wiring layers are in electrical communication.

In accordance with at least one embodiment of the present invention, anelectronic apparatus is provided, the electronic apparatus comprising anoptical unit, and a solid-state imaging device, the solid state imagedevice including a first semiconductor section including a first wiringlayer at one side thereof, the first semiconductor section furtherincluding a circuit region and a pixel region, a second semiconductorsection including a second wiring layer at one side thereof, the firstand second semiconductor sections being secured together, a thirdsemiconductor section including a third wiring layer at one sidethereof, the second and the third semiconductor sections being securedtogether such the first semiconductor section, second semiconductorsection, and the third semiconductor section are stacked together, and afirst conductive material electrically connecting at least two of (i)the first wiring layer, (ii) the second wiring layer, and (iii) thethird wiring layer such that the electrically connected wiring layersare in electrical communication.

Other systems, methods, features, and advantages of the presentinvention will be or will become apparent to one with skill in the artupon examination of the following figures and detailed description. Itis intended that all such additional systems, methods, features, andadvantages be within this description, be within the scope of theinvention, and be protected by the accompanying claims.

Advantageous Effects of the Invention

According to the present technology, it is possible to easily provide ahigh-quality stacked image sensor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view illustrating a configuration of a pixelportion of a stacked solid-state imaging device in the related art.

FIG. 2 is a cross-sectional view illustrating another configuration ofthe pixel portion of the stacked solid-state imaging device in therelated art.

FIG. 3 is a diagram illustrating a manufacturing method of a three-layerstacked solid-state imaging device.

FIG. 4 is a diagram illustrating a manufacturing method of thethree-layer stacked solid-state imaging device.

FIG. 5 is a cross-sectional view illustrating a configuration of a pixelportion of a solid-state imaging device with a three-layer stackedstructure manufactured according to FIGS. 3 and 4.

FIG. 6 is a cross-sectional view illustrating a configuration accordingto an embodiment of a pixel portion of a solid-state imaging device towhich the present technology is applied.

FIG. 7A is an enlarged view in the vicinity of the pad hole.

FIG. 7B is a diagram in which the aluminum pad is viewed from the top ofthe pad hole.

FIG. 8 is a cross-sectional view illustrating a configuration accordingto another embodiment of the pixel portion of the solid-state imagingdevice to which the present technology is applied.

FIG. 9 is a cross-sectional view illustrating a configuration accordingto still another embodiment of the pixel portion of the solid-stateimaging device to which the present technology is applied.

FIG. 10 is a diagram illustrating a schematic configuration of asolid-state imaging device to which the present technology is applied.

FIG. 11 is a schematic diagram of the cross-sectional view related tothe configuration of the pixel portion of the solid-state imaging deviceshown in FIG. 6.

FIG. 12 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

FIG. 13 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 14 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 15 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 16 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 17 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 18 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 19 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 12.

FIG. 20 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

FIG. 21 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 22 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 23 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 24 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 25 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 26 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 27 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 20.

FIG. 28 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

FIG. 29 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

FIG. 30 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 29.

FIG. 31 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 29.

FIG. 32 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 29.

FIG. 33 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 29.

FIG. 34 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 29.

FIG. 35 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

FIG. 36 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 35.

FIG. 37 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 35.

FIG. 38 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 35.

FIG. 39 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 35.

FIG. 40 is a diagram illustrating a manufacturing process of thesolid-state imaging device shown in FIG. 35.

FIG. 41 is a diagram illustrating a combination of configurations whichmay be employed as an embodiment of a solid-state imaging device towhich the present technology is applied.

FIG. 42 is a schematic diagram of a cross-sectional view illustrating aconfiguration of a pixel portion of a solid-state imaging device towhich the present technology is applied in a case of employing afour-layer structure.

FIG. 43 is a block diagram illustrating a configuration example of anelectronic apparatus to which the present technology is applied.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the technology disclosed herein will bedescribed with reference to the drawings.

First, problems of the related art will be described.

As solid-state imaging devices, there is an amplification typesolid-state imaging device represented by a MOS type image sensor suchas a complementary metal oxide semiconductor (CMOS). In addition, thereis a charge transfer type solid-state imaging device represented by acharge coupled device (CCD).

These solid-state imaging devices are frequently used in digital stillcameras, digital video cameras, and the like. In recent years, assolid-state imaging devices have been mounted in mobile apparatuses suchas, mobile phones and personal digital assistants (PDAs) with cameras, aMOS type image sensor has been frequently used from the viewpoint of alow power supply voltage, power consumption, and the like.

The MOS type solid-state imaging device includes a pixel array (pixelregion) in which a plurality of unit pixels are arranged in atwo-dimensional array and a peripheral circuit region, and each of theunit pixels includes a photo diode which is a photoelectric conversionportion and a plurality of pixel transistors. A plurality of pixeltransistors are formed of MOS transistors, and generally comprise threetransistors including a transfer transistor, a reset transistor, anamplification transistor, or four transistors additionally including aselection transistor.

In addition, in the above-described solid-state imaging device, astacked structure has been proposed in which a plurality ofsemiconductor substrates having different functions are stacked in anoverlapping manner and are electrically connected to each other.

In the stacked structure, since each circuit can be formed optimally soas to correspond to the function of each semiconductor substrate, it ispossible to easily realize high performance of a device.

For example, it is possible to manufacture a high performancesolid-state imaging device by optimally forming a sensor circuit and alogical circuit so as to correspond to respective functions of asemiconductor substrate including the sensor circuit and a semiconductorsubstrate including the logical circuit in which a circuit processingsignals is provided. At this time, through electrodes are provided insubstrates of the semiconductor substrates, and thereby the plurality ofsemiconductor substrates are electrically connected to each other.

FIG. 1 is a cross-sectional view illustrating a configuration of a pixelportion of a stacked solid-state imaging device in the related art.

A solid-state imaging device related to this pixel portion includes arear surface irradiation type CMOS image sensor which is formed bystacking a first semiconductor substrate and a second semiconductorsubstrate. In other words, the solid-state imaging device shown in FIG.1 has a two-layer stacked structure.

As shown in FIG. 1, an image sensor, that is, a pixel array(hereinafter, referred to as a pixel region) and a control region isformed in each region of the first semiconductor substrate 31.

That is, a photodiode (PD) 34 which is a photoelectric conversionportion of each pixel is formed in each region of the semiconductorsubstrate (for example, a silicon substrate) 31, and a source/drainregion of each pixel transistor is formed in a semiconductor well regionthereof.

A gate electrode is formed on a substrate surface forming the pixel viaa gate insulating film, and a pixel transistor Tr1 and a pixeltransistor Tr2 are formed by the gate electrode and the source/drainregion corresponding thereto.

The pixel transistor Tr1 adjacent to the photodiode (PD) 34 correspondsto a transfer transistor, and the source/drain region corresponds to afloating diffusion (FD).

Next, an interlayer insulating film 39 of the first layer is formed onthe surface of the first semiconductor substrate 31, then a connectionhole is formed in the interlayer insulating film 39, and connectionconductors which are connected to necessary transistors are formedtherein.

Successively, a metal wire of a plurality of layers (in this example,two layers) is formed via the interlayer insulating film 39 so as to beconnected to each connection conductor, thereby forming a multilayerwire layer 41. The metal wire is formed of a copper (Cu) wire.Generally, each copper wire (meal wire) is covered with a barrier metalfilm for preventing diffusion of Cu. For this reason, a protective filmwhich is a cap film of the copper wire is formed on the multilayer wirelayer 41.

The first semiconductor substrate 31 having the pixel region and thecontrol region is formed through the steps hitherto.

On the other hand, for example, a logical circuit having a signalprocessing circuit which controls the pixel region or controlscommunication with an external device and is related to signalprocessing is formed in each region of the second semiconductorsubstrate 45. In other words, a plurality of MOS transistor Tr6, MOStransistor Tr7, and MOS transistor Tr8 which form the logical circuit soas to be separated by element separation regions are formed in a p typesemiconductor well region on the front surface side of the semiconductorsubstrate (for example, a silicon substrate) 45.

Next, an interlayer insulating film 49 of the first layer is formed onthe surface of the second semiconductor substrate 45, then a connectionhole is formed in the interlayer insulating film 49, and connectionconductors 54 which are connected to necessary transistors are formedtherein.

Successively, a metal wire of a plurality of layers, in this example,four layers, is formed via the interlayer insulating film 49 so as to beconnected to each connection conductor 54, thereby forming a multilayerwire layer 55.

The metal wire is formed of a copper (Cu) wire. A protective film whichis a cap film of the copper wire (metal wire) is formed on themultilayer wire layer 55. However, the uppermost layer of the multilayerwire layer 55 is formed of an aluminum pad which may be an electrode.

The second semiconductor substrate 45 having the logical circuit isformed through the steps hitherto.

In addition, the first semiconductor substrate 31 and the secondsemiconductor substrate 45 are joined to each other such that themultilayer wire layer 41 and the multilayer wire layer 55 face eachother at a bonding surface 99. The joining is performed using, forexample, plasma bonding and adhesive bonding.

In addition, grinding and polishing are performed from a rear surface 31b side of the first semiconductor substrate 31 so as to thin the firstsemiconductor substrate 31, and the rear surface of the firstsemiconductor substrate 31 is a light incident surface in a rear surfaceirradiation type solid-state imaging device.

Through connection holes, which penetrate through the firstsemiconductor substrate 31 from the rear surface side and reach thealuminum pad of the uppermost layer of the multilayer wire layer 55 ofthe second semiconductor substrate 45, are formed at necessary positionsof the thinned first semiconductor substrate 31. In addition, aconnection hole, which reaches the wire of the first layer of the firstsemiconductor substrate 31 side from the rear surface side, is formed inthe first semiconductor substrate 31 around the through connection hole.

Next, a through connection conductor 64 and a connection conductor 65are embedded in the through connection holes. The through connectionconductor 64 and the connection conductor 65 may use, for example, ametal such as copper (Cu) or tungsten (W).

As described above, since the logical circuit performing signalprocessing is formed in the second semiconductor substrate 45, it isnecessary to input and output signals by connecting electrodes of therespective transistors to signal lines. That is, the logical circuit isoperated based on input and output of signals with an external device.Therefore, the aluminum pad 53 of the second semiconductor substrate 45is an electrode for external connection.

For this reason, a pad hole 81 which penetrates through the firstsemiconductor substrate 31 is formed so as to be wire-bonded to thealuminum pad 53 of the second semiconductor substrate, thereby exposingthe aluminum pad 53.

Next, an insulating protective film is formed on the entire rear surfaceof the first semiconductor substrate 31 such that a light blocking film67 is formed in a region which it is necessary to block light fromreaching. For example, a metal film such as tungsten may be used as thelight blocking film 67.

Successively, a planarized film is formed on the light blocking film 67,on-chip color filters 74 of, for example, red (R), green (G), and blue(B) corresponding to the respective pixels are formed on the planarizedfilm, and an on-chip micro lens 75 is formed thereon.

In addition, the pad hole 81 is formed in the first semiconductorsubstrate 31 so as to reach the aluminum pad 53 which is an electrodeused for transmission, reception, and the like of signals with anexternal apparatus or circuit, from the rear surface side (lightreceiving surface side) of the first semiconductor substrate 31.

Thus, the process for the stacked semiconductor structure is completed.In other words, the pixel region and the control region are formed inthe first semiconductor substrate 31, and the logical circuit is formedin the second semiconductor substrate 45.

Subsequently, the stacked semiconductor structure is divided intosubstrates which correspond to a substrate of the rear surfaceirradiation type solid-state imaging device.

In addition, in the solid-state imaging device with the stackedstructure, it is also necessary to take into consideration the influenceof noise and the like due to hot carriers. The hot carriers may behigh-speed electrons having high kinetic energy that come out of atransistor and generate light when the high-speed electrons impactsilicon atoms.

In the solid-state imaging device with the stacked structure,transistors are provided in the second semiconductor substrateseparately from the first semiconductor substrate in which the PD isprovided. For this reason, light generated by hot carriers coming out ofthe transistors of the second semiconductor substrate penetrates fromthe rear side (the opposite side to the light receiving surface) of thePD of the first semiconductor substrate, thereby causing noise.

For this reason, in the solid-state imaging device with the stackedstructure, in order to block light caused by the hot carriers forexample, a preventative measure, such as providing a light blocking bodyis performed.

FIG. 2 is a cross-sectional view illustrating another configuration ofthe pixel portion of the stacked solid-state imaging device in therelated art.

In the example shown in FIG. 2, a light blocking body 90 is formed underthe PD 34 in the first semiconductor substrate 31. Thus, light caused byhot carriers coming out of the MOS transistor Tr6, the MOS transistorTr7, and the MOS transistor Tr8 of the second semiconductor substrate 45is blocked.

Alternatively, a shape of the copper wire of the multilayer wire layer55 may be changed, or the like, so as to block light caused by hotcarriers coming out of the MOS transistor Tr6, the MOS transistor Tr7,and the MOS transistor Tr8.

As described above with reference to FIGS. 1 and 2, in the solid-stateimaging device with the two-layer stacked structure, the pad hole 81 isprovided so as to be electrically connected to an external device, andlight caused by the hot carriers is blocked using the light blockingbody 90 or a shape of the copper wire of the multilayer wire layer 55.

A three-layer stacked solid-state imaging device has been developed. Thethree-layer stacked solid-state imaging device includes, for example, athird semiconductor substrate in which a memory circuit is formed inaddition to the first semiconductor substrate in which the pixel regionand the control region (hereinafter, referred to as a sensor circuit)and the second semiconductor substrate in which the logical circuit isformed.

The three-layer stacked solid-state imaging device is manufactured, forexample, as shown in FIGS. 3 and 4.

First, as shown in FIG. 3, a second semiconductor substrate 112 and athird semiconductor substrate 113 are joined together such that circuitsurfaces thereof face each other. In addition, interlayer films of thetwo semiconductor substrates are joined to each other. Further, thesecond semiconductor substrate 112 is thinned.

Next, as shown in FIG. 4, a first semiconductor substrate 111 is joinedonto the thinned second semiconductor substrate 112 in a state where therear surface thereof face upward. In addition, interlayer films of thetwo semiconductor substrates are joined to each other. Further, thefirst semiconductor substrate 111 is thinned.

As above, in a case where a stacked image sensor is formed using thethree-layer stacked structure, it is necessary for the sensor circuithaving a light receiving portion to incorporate light, and thus thesensor circuit is disposed in the uppermost part, and the two logicalcircuit and memory circuit are stacked in lower layers thereof.

In addition, when the circuits are stacked, it is preferable that asupport substrate for thinning a silicon substrate not be used. For thisreason, in manufacturing circuits, first, the circuit surfaces of twosemiconductor substrates of the lower layers are joined together so asto face each other, and the semiconductor substrate (the secondsemiconductor substrate 112) of the second layer is thinned. Thereafter,the semiconductor substrate (the first semiconductor substrate 111) ofthe uppermost layer is joined thereto so as to be stacked thereon as arear surface type, and is further thinned.

However, in this way, the inventors have found that the followingproblems occur in the three-layer stacked structure.

FIG. 5 is a cross-sectional view illustrating a configuration of a pixelportion of a three-layer stacked solid-state imaging device manufacturedaccording to FIGS. 3 and 4.

A first problem in the three-layer stacked structure in FIG. 5 is that apad hole is too deep. In FIG. 5, a pad hole 121 which is deeper than thepad hole 81 of FIG. 1 is formed.

In other words, in the three-layer stacked structure, as described withreference to FIGS. 3 and 4, the circuit surface of the secondsemiconductor substrate 112 is joined to the circuit surface of thethird semiconductor substrate so as to face each other. For this reason,an aluminum pad of the uppermost layer of the multilayer wire layer ofthe second semiconductor substrate is distant from the light receivingsurface of the first semiconductor substrate 111, and thus the aluminumpad 133 (an electrode for external connection) of the secondsemiconductor substrate is not exposed unless an opening is formed so asto penetrate through the first semiconductor substrate and, further,substantially penetrate through the second semiconductor substrate.

In order to open the deep pad hole 121, thickening of a resist isnecessary. If the resist is thickened in order to open the deep pad hole121, curing of the resist after dry etching is problematic.

For example, since an on-chip micro lens using an organic material hasalready been formed on the first semiconductor substrate when theopening is formed, the resist is removed using a solution, but the curedresist tends to remain in a residual state and thus impedes lightincidence to the lens.

In addition, in a case where the deep pad hole 121 is opened, adeposited substance occurring as a result of the dry etching is alsoproblematic.

Particularly, a deposited substance which is attached to the surface ofthe aluminum pad 133 or the sidewall of the pad hole 121 and is notremoved, for example, absorbs humidity so as to generate fluorine ionsafter the three-layer stacked structure is completed, and thus causes adefect (corrosion) in which the aluminum pad metal melts.

As above, in FIGS. 3 and 4, it is difficult to perform a manufacturingprocess of a solid-state imaging device due to the deep pad hole.

A second problem in the three-layer stacked structure in FIG. 5 is thatit is difficult to block light caused by hot carriers.

In other words, in using the three-layer stacked structure, as describedwith reference to FIGS. 3 and 4, the circuit surface of the secondsemiconductor substrate 112 is joined to the circuit surface of thethird semiconductor substrate so as to face each other. For this reason,a transistor of the second semiconductor substrate faces the firstsemiconductor substrate without using the multilayer wire layer.Therefore, for example, in the same manner as a case of the two-layerstacked structure, light caused by hot carriers is unable to be blockedby the copper wire of the multilayer wire layer of the secondsemiconductor substrate.

Therefore, in the present technology, it is not necessary to provide adeep pad hole; therefore, light caused by hot carriers can be easilyblocked.

FIG. 6 is a cross-sectional view illustrating a configuration accordingto an embodiment of a pixel portion of a solid-state imaging device towhich the present technology is applied. A solid-state imaging devicerelated to this pixel portion includes a rear surface irradiation typeCMOS image sensor formed by stacking a first semiconductor substrate, asecond semiconductor substrate, and a third semiconductor substrate. Inother words, the solid-state imaging device related to the pixel portionshown in FIG. 6 has a three-layer stacked structure.

In addition, the solid-state imaging device includes, for example, afirst semiconductor substrate provided with a sensor circuit, a secondsemiconductor substrate provided with a logical circuit, and a thirdsemiconductor substrate provided with a memory circuit. The logicalcircuit and the memory circuit are respectively operated based on inputand output of signals with an external device.

As shown in FIG. 6, a photodiode (PD) 234 which is a photoelectricconversion portion of each pixel is formed in the semiconductorsubstrate (for example, a silicon substrate) 211, and a source/drainregion of each pixel transistor is formed in a semiconductor well regionthereof.

A gate electrode is formed on a substrate surface forming the pixel viaa gate insulating film, and a pixel transistor Tr1 and a pixeltransistor Tr2 are formed by the gate electrode and the source/drainregion corresponding thereto.

The pixel transistor Tr1 adjacent to the photodiode (PD) 234 correspondsto a transfer transistor, and the source/drain region corresponds to afloating diffusion (FD).

In addition, an interlayer insulating film is formed in the firstsemiconductor substrate 211, connection hole are formed in theinterlayer insulating film, and connection conductors 244 connected tothe pixel transistor Tr1 and the pixel transistor Tr2 are formedtherein.

In addition, in order to be connected to each connection conductor 244,a metal wire 240 of a plurality of layers is formed so as to form amultilayer wire layer 245. The metal wire 240 is formed of a copper (Cu)wire. Generally, each copper wire is covered with a barrier metal filmfor preventing diffusion of Cu. For this reason, a protective film whichis a cap film of the copper wire is formed on the multilayer wire layer245.

In addition, an aluminum pad 280 which is an electrode for externalconnection is formed in the lowermost layer of the multilayer wire layer245 of the first semiconductor substrate 211. In other words, thealuminum pad 280 is formed at a position closer to an adhesive surface291 with the second semiconductor substrate 212 than the copper wire240. This electrode for external connection is used as one end of a wirerelated to input and output of a signal with an external device. Inaddition, although the electrode has been described as being made ofaluminum, the electrode may be made of other metals.

In addition, a contact 265 which is used for electrical connection tothe second semiconductor substrate 212 is formed in the firstsemiconductor substrate 211. The contact 265 is connected to a contact311 of the second semiconductor substrate 212, described later, and isalso connected to an aluminum pad 280 a of the first semiconductorsubstrate 211.

In addition, a pad hole 351 is formed in the first semiconductorsubstrate 211 so as to reach the aluminum pad 280 a from the rearsurface side (the light receiving surface side) of the firstsemiconductor substrate 211.

FIGS. 7A and 7B are diagrams illustrating a configuration of the padhole 351 and the aluminum pad 280 a. FIG. 7A is an enlarged view of thevicinity of the pad hole 351, and

FIG. 7B is a diagram in which the aluminum pad 280 a is viewed from thetop of the pad hole 351.

As shown in FIG. 7B, a plurality of contacts 265 are arranged and areconnected to an end of the aluminum pad 280 a so as to reduce contactresistance.

Returning to FIG. 6, in the same manner as the case described withreference to FIG. 1, an insulating protective film is formed on theentire rear surface in the first semiconductor substrate 211 so as toform a light block film in a region which it is necessary to block lightfrom reaching. Further, on-chip color filters 274 which correspond tothe respective pixels are formed on the planarized film, and an on-chipmicro lens 275 is formed thereon.

Meanwhile, a logical circuit is formed in the second semiconductorsubstrate 212. In other words, a MOS transistor Tr6, a MOS transistorTr7, and a MOS transistor Tr8 which comprise a plurality of transistorsforming the logical circuit, are formed in a p type semiconductor wellregion of the semiconductor substrate (for example, a silicon substrate)212.

In addition, connection conductors 254 which are connected to the MOStransistor Tr6, the MOS transistor Tr7, and the MOS transistor Tr8 areformed in the second semiconductor substrate 212.

In addition, a metal wire 250 of a plurality of layers is formed, and amultilayer wire layer 255 is formed so as to be connected to therespective connection conductors 254.

The metal wire is formed of a copper (Cu) wire. A protective film whichis a cap film of the copper wire (metal wire) 250 is formed on themultilayer wire layer 255.

In addition, an aluminum pad 320 which is an electrode is formed in thelowermost layer of the multilayer wire layer 255 of the secondsemiconductor substrate 212.

Further, a contact 311 which is used for electrical connection to thefirst semiconductor substrate 211 and the third semiconductor substrate213 is formed in the second semiconductor substrate 212. The contact 311is connected to the contact 265 of the first semiconductor substrate 211and is also connected to an aluminum pad 330 a of the thirdsemiconductor substrate 213.

In addition, a memory circuit is formed in the third semiconductorsubstrate 213. In other words, a MOS transistor Tr11, a MOS transistorTr12, and a MOS transistor Tr13 which are a plurality of transistorsforming the memory circuit are formed in a p type semiconductor wellregion of the semiconductor substrate (for example, a silicon substrate)213.

In addition, connection conductors 344 which are connected to the MOStransistor Tr11, the MOS transistor Tr12, and the MOS transistor Tr13are formed in the third semiconductor substrate 213.

In addition, a metal wire 340 of a plurality of layers is formed, and amultilayer wire layer 345 is formed so as to be connected to therespective connection conductors 344.

The metal wire is formed of a copper (Cu) wire. A protective film whichis a cap film of the copper wire (metal wire) 340 is formed on themultilayer wire layer 345. In addition, an aluminum pad 330 which is anelectrode is formed in the uppermost layer of the multilayer wire layer345. In the solid-state imaging device shown in FIG. 6, the contact 265and the contact 311 are provided, and thus input and output of signalscan be performed between the first semiconductor substrate 211 to thethird semiconductor substrate 213 via the aluminum pad 280 a.

Also in the solid-state imaging device shown in FIG. 6, as describedwith reference to FIGS. 3 and 4, interlayer films of the secondsemiconductor substrate 212 and the third semiconductor substrate 213are joined to each other at an adhesive surface 292. In addition, theinterlayer films of the second semiconductor substrate 212 and the firstsemiconductor substrate 211 are joined to each other at the adhesivesurface 291.

In other words, as described with reference to FIGS. 3 and 4, first, thetwo semiconductor substrates of the lower layers are joined togethersuch that the circuit surfaces thereof face each other, and thesemiconductor substrate (the second semiconductor substrate 212) of thesecond layer is thinned. Next, the semiconductor substrate (the firstsemiconductor substrate 211) of the uppermost layer is joined thereto soas to be stacked thereon as a rear surface type, and is further thinned.At this time, after the upper layer of the contact 311 is planarized,the first semiconductor substrate 211 is joined to the secondsemiconductor substrate 212 as a rear surface type.

In this way, when the circuits are stacked, a support substrate forthinning the silicon substrate is not used.

In the present technology, the aluminum pad 280 is also provided in thefirst semiconductor substrate 211. In addition, an electrode for anexternal electrode is not provided in the second semiconductor substrate212 having the logical circuit in which input and output of signals toand from an external device are necessary, or the third semiconductorsubstrate 213 having the memory circuit, and an electrode (the aluminumpad 280 a) for an external connection is provided in the firstsemiconductor substrate 211 having the sensor circuit.

In this way, it is possible to expose the electrode for externalconnection without deepening the pad hole 351.

In addition, in the present technology, since the aluminum pad 280 isalso provided in the first semiconductor substrate 211, it is possibleto block light caused by hot carriers coming out of each transistor ofthe second semiconductor substrate 212 by the aluminum pad 280.

As above, in the present technology, it is not necessary to provide adeep pad hole, and it is possible to easily prevent the influence ofnoise and the like due to hot carriers by blocking the light caused byhot carriers.

In addition, and with respect to FIG. 6, although the aluminum pad 320is provided in the second semiconductor substrate and the aluminum pad330 is provided in the third semiconductor substrate 213, the aluminumpad 320 and the aluminum pad 330 may not be provided. For example, ifthe contact 311 is to be directly connected to the copper wire 340 ofthe third semiconductor substrate 213, it is unnecessary to provide thealuminum pad 320 and the aluminum pad 330.

In addition, a shape of the contact which electrically connects thesemiconductor substrates to each other is not limited to the shapes ofthe contact 265 and the contact 311. In addition, since a hole forforming a contact can be formed before an on-chip micro lens is formed,even the problem associated with a deep pad hole is not an issue. Forexample, a contact may be provided which penetrates through the secondsemiconductor substrate so as to connect the copper wire of the firstsemiconductor substrate to the copper wire of the third semiconductorsubstrate.

Alternatively, a light blocking body which blocks light caused by hotcarriers may be formed.

FIG. 8 is a cross-sectional view illustrating a configuration accordingto another embodiment of the pixel portion of the solid-state imagingdevice to which the present technology is applied. In the same manner asin FIG. 6, a solid-state imaging device related to this pixel portionincludes a rear surface type CMOS image sensor formed by stacking afirst semiconductor substrate, a second semiconductor substrate, and athird semiconductor substrate. In other words, the solid-state imagingdevice related to the pixel portion shown in FIG. 8 also has athree-layer stacked structure.

In the example shown in FIG. 8, a light blocking body 360 is disposed inan interlayer film which is the uppermost layer of the secondsemiconductor substrate 212 in FIG. 8. Thus, it is possible to morereliably block light caused by hot carriers coming out of eachtransistor of the second semiconductor substrate 212.

In addition, since the aluminum pad 280 is formed in the firstsemiconductor substrate 211, the light blocking body 360 is not disposedin the first semiconductor substrate 211 and is disposed in theinterlayer film of the second semiconductor substrate 212.

The other constituent elements in FIG. 8 are the same as in the casedescribed with reference to FIG. 6, and thus detailed descriptionthereof will be omitted.

Alternatively, a copper wire may be formed in the interlayer film whichis the uppermost layer of the second semiconductor substrate 212 in FIG.8, and light caused by hot carriers may be blocked by a combination ofthe aluminum pad and the copper wire.

FIG. 9 is a cross-sectional view illustrating a configuration accordingto still another embodiment of the pixel portion of the solid-stateimaging device to which the present technology is applied. In the samemanner as in FIG. 6, a solid-state imaging device related to this pixelportion includes a rear surface irradiation type CMOS image sensorformed by stacking a first semiconductor substrate, a secondsemiconductor substrate, and a third semiconductor substrate. In otherwords, the solid-state imaging device related to the pixel portion shownin FIG. 9 also has a three-layer stacked structure.

In the example shown in FIG. 9, a copper wire 370 is disposed in aninterlayer film which is the uppermost layer of the second semiconductorsubstrate 212 in FIG. 9.

A part of the contact 311 is formed in the interlayer film which is theuppermost layer of the second semiconductor substrate 212 in FIG. 9. Forexample, if the copper wire 370 is further formed in the interlayer filmwhen the contact 311 is formed, a solid-state imaging device with theconfiguration shown in FIG. 9 can be obtained.

When light is blocked by a combination of the copper wire 370 and thealuminum pad 280, it is possible to more reliably block light caused byhot carriers coming out of each transistor of the second semiconductorsubstrate 212. In addition, in an embodiment of the configuration shownin FIG. 9, additional freedom in designing wires related to the aluminumpad 280 may be utilized, as compared with a case of blocking light onlyby the aluminum pad 280, for example, as shown in FIG. 6.

The other constituent elements in FIG. 9 are the same as in the casedescribed with reference to FIG. 6, and thus detailed descriptionthereof will be omitted.

FIG. 10 is a diagram illustrating a schematic configuration of asolid-state imaging device to which the present technology is applied.This solid-state imaging device 401 includes, for example, a CMOS imagesensor.

The solid-state imaging device 401 of FIG. 10 includes a pixel region (aso-called pixel array) 403 in which pixels 402 including a plurality ofphotoelectric conversion portions are regularly arranged in atwo-dimensional array on the semiconductor substrate 411 and aperipheral circuit portion.

Each of the pixels 402 includes, for example, a photodiode which is thephotoelectric conversion portion and a plurality of pixel transistors(so-called MOS transistors).

In addition, the pixels 402 may have a shared pixel structure. Thispixel shared structure is formed by a plurality of photodiodes, aplurality of transfer transistors, a single shared floating diffusion,and another shared transistor.

The peripheral circuit portion includes a vertical driving circuit 404,a column signal processing circuit 405, a horizontal driving circuit406, an output circuit 407, a control circuit 408, and the like.

The control circuit 408 receives an input clock and data for commandingan operation mode and the like, and outputs data such as internalinformation of the solid-state imaging device. In other words, thecontrol circuit 408 generates a clock signal used as a reference ofoperations of the vertical driving circuit 404, the column signalprocessing circuit 405, the horizontal driving circuit 406, and thelike, and control signals on the basis of a vertical synchronizationsignal, a horizontal synchronization signal, and a master clock. Inaddition, these signals are input to the vertical driving circuit 404,the column signal processing circuit 405, the horizontal driving circuit406, and the like.

The vertical driving circuit 404 including, for example, shiftregisters, selects a pixel driving line, and supplies a pulse fordriving the pixels to the selected pixel driving line so as to drive thepixels in the unit of a row. In other words, the vertical drivingcircuit 404 sequentially selectively scans the respective pixels 402 ofthe pixel region 403 in the vertical direction in the unit of a row, andsupplies a pixel signal based on signal charge which is generatedaccording to a light receiving amount in, for example, the photodiodewhich is a photoelectric conversion portion of each pixel 402, to thecolumn signal processing circuit 405 via a vertical signal line 409.

The column signal processing circuit 405 is disposed, for example, foreach column of the pixels 402, and performs a signal process such asnoise removal on signals output from the pixels 402 of one row for eachpixel column. In other words, the column signal processing circuit 405performs signal processes such as CDS for removing fixed pattern noiseunique to the pixels 402, signal amplification, and AD conversion. In anoutput end of the column signal processing circuit 405, a horizontalselection switch (not shown) is provided so as to be connected to ahorizontal signal line 410.

The horizontal driving circuit 406 includes, for example, shiftregisters, sequentially outputs horizontal scanning pulses so as tosequentially select the respective column signal processing circuits405, thereby outputting a pixel signal from each of the column signalprocessing circuits 405 to the horizontal signal line 410.

The output circuit 407 performs a signal process on the signals whichare sequentially supplied from the respective column signal processingcircuits 405 via the horizontal signal line 410 so as to be output. Forexample, only buffering may be performed, or black level adjustment,column disparity correction, a variety of digital signal processes, andthe like may be performed. An input and output terminal 412 sends andreceives signals to and from an external device.

The solid-state imaging device 401 shown in FIG. 10 includes a rearsurface irradiation type CMOS image sensor with a three-layer stackedstructure. For example, the pixels 402 shown in FIG. 10 are sensorcircuits formed in the first semiconductor substrate, and the peripheralcircuits are logical circuits formed in the second semiconductorsubstrate or memory circuits formed in the third semiconductorsubstrate.

In the above-described embodiment, and as previously described, thealuminum pad 280 is formed in the lowermost layer of the multilayer wirelayer 245 of the first semiconductor substrate 211. However, forexample, in a case where the aluminum pad 280 is disposed in the firstsemiconductor substrate 211, it is necessary to provide anelectro-static discharge (ESD) circuit which is a circuit for protectingcircuits of the first semiconductor substrate 211 from overcurrent, andthis increases the number of steps.

In addition, in the above example described with reference to FIG. 6, itis possible to achieve an effect in which light caused by hot carriersis blocked by the aluminum pad 280 disposed in the first semiconductorsubstrate 211. However, since the multilayer wire layer 245 of the firstsemiconductor substrate 211 includes three wire layers, it is difficultto dispose the aluminum pad 280 so as to block light caused by hotcarriers without restricting a shape of the copper wire 240.

For example, since the multilayer wire layer 255 of the secondsemiconductor substrate 212 includes six wire layers, if the aluminumpad 280 is disposed in the second semiconductor substrate 212, it iseasy to dispose the aluminum pad 280 so as to block light caused by hotcarriers without restricting a shape of the metal wire 250.

In addition, in the above-described embodiment, the contact 265 used forelectrical connection between the first semiconductor substrate 211 andthe second semiconductor substrate 212 has a configuration in whichconductors embedded in two through holes which penetrate through thefirst semiconductor substrate 211 in the vertical direction areconnected to each other on the light receiving surface (the uppermostsurface in FIG. 9) of the first semiconductor substrate 211. Thiscontact is also referred to as a twin contact. The contact 311 used forelectrical connection between the second semiconductor substrate 212 andthe third semiconductor substrate 213 is also a twin contact.

However, since it is necessary to provide two through holes for the twincontact, the number of manufacturing steps increases, and the areaoccupying the substrate also increases.

For example, when a contact is formed which penetrates through the firstsemiconductor substrate 211 from the uppermost side of the firstsemiconductor substrate 211 in FIG. 9 and reaches the wire inside themultilayer wire layer 255 of the second semiconductor substrate, a partof which reaches the wire inside the multilayer wire layer 245 of thefirst semiconductor substrate 211, only a single through hole isprovided and thereby the first semiconductor substrate 211 can beelectrically connected to the second semiconductor substrate 212. Thiscontact is also referred to as a shared contact.

When the shared contact is used for electrical connection between thesemiconductor substrates, manufacturing steps can be simplified and thusthe area occupying the substrate can be reduced as compared with a caseof using the twin contact.

In addition, when semiconductor substrates are joined together, a methodin which the copper wires of the multilayer wire layers are directlybonded to each other has been utilized. If the copper wires of themultilayer wire layers are directly bonded to each other, it isunnecessary to provide a contact for electrical connection betweensemiconductor substrates, manufacturing steps can be further simplified,and thus the area occupying the substrate can be reduced. In addition,the method of directly bonding the copper wires to each other is alsoreferred to as direct bonding.

FIG. 11 is a schematic diagram of the cross-sectional view related tothe configuration of the pixel portion of the solid-state imaging deviceshown in FIG. 6. As shown in FIG. 11, the pad hole 351 is formed in thefirst semiconductor substrate 211 so as to reach the aluminum pad 280 afrom the rear surface side (light receiving surface side) of the firstsemiconductor substrate 211. In addition, the aluminum pad 280 is formedin the multilayer wire layer 245 of the first semiconductor substrate211.

Further, in the configuration shown in FIG. 11, the multilayer wirelayer 255 of the second semiconductor substrate faces the thirdsemiconductor substrate 213 side (the lower side of FIG. 11), and thefirst semiconductor substrate 211 is joined to the second semiconductorsubstrate 212.

In addition, in the configuration shown in FIG. 11, the contact 265 usedfor electrical connection between the first semiconductor substrate 211and the second semiconductor substrate 212 and the contact 311 used forelectrical connection between the second semiconductor substrate 212 andthe third semiconductor substrate 213 are provided. The contact 265 andthe contact 311 are respectively formed by a twin contact.

FIG. 12 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

In the configuration shown in FIG. 12, unlike in the case of FIG. 11,the multilayer wire layer 255 of the second semiconductor substratefaces the first semiconductor substrate 211 side (the upper side in FIG.12), and the first semiconductor substrate 211 is joined to the secondsemiconductor substrate 212.

In addition, in the configuration shown in FIG. 12, unlike in the caseof FIG. 11, the aluminum pad 280 is provided in the multilayer wirelayer 255 of the second semiconductor substrate 212. Further, the padhole 351 is formed in the first semiconductor substrate 211 so as toreach the aluminum pad 280 a from the rear surface side (light receivingsurface side) of the first semiconductor substrate 211.

As shown in FIG. 12, the multilayer wire layer 255 of the secondsemiconductor substrate 212 faces the first semiconductor substrateside, and thus light caused by hot carriers can be blocked by themultilayer wire layer 255. In addition, the aluminum pad 280 is disposedin the multilayer wire layer 255 including the six wire layers, and thusit is easy to dispose the aluminum pad 280 so as to block light causedby hot carriers without restricting a shape of the metal wire 250.

In addition, since the aluminum pad 280 is provided in the multilayerwire layer 255 of the second semiconductor substrate 212, it isunnecessary to provide an ESD circuit in the first semiconductorsubstrate 211 (because an ESD circuit is preferably formed in the secondsemiconductor substrate), and thus it is possible to manufacture asolid-state imaging device at a low cost.

In addition, in the configuration shown in FIG. 12, the contact 266 usedfor electrical connection between the first semiconductor substrate 211and the second semiconductor substrate 212 and the contact 312 used forelectrical connection between the second semiconductor substrate 212 andthe third semiconductor substrate 213 are provided. The contact 266 andthe contact 312 are respectively formed by a twin contact.

In a case of the configuration shown in FIG. 12, unlike in the case ofFIG. 11, the contact 312 penetrates through the first semiconductorsubstrate 211 and the second semiconductor substrate 212 and reaches themultilayer wire layer 345 of the third semiconductor substrate 213.

Next, a manufacturing process of the solid-state imaging device shown inFIG. 12 will be described.

First, as shown in FIG. 13, the first semiconductor substrate 211, thesecond semiconductor substrate 212, and the third semiconductorsubstrate 213 are prepared which are respectively provided with themultilayer wire layers. As shown in FIG. 13, the first semiconductorsubstrate 211 is provided with the multilayer wire layer 245, the secondsemiconductor substrate 212 is provided with the multilayer wire layer255, and the third semiconductor substrate 213 is provided with themultilayer wire layer 345.

In addition, as shown in FIG. 13, the aluminum pad 280 is formed in themultilayer wire layer 255 of the second semiconductor substrate 212.

Next, as shown in FIG. 14, the first semiconductor substrate 211 isjoined to the second semiconductor substrate 212. At this time, thefirst semiconductor substrate 211 is joined to the second semiconductorsubstrate 212 such that the multilayer wire layer 245 and the multilayerwire layer 255 face each other.

In addition, as shown in FIG. 15, the second semiconductor substrate 212is thinned. In FIG. 15, the width of the second semiconductor substrate212 in the vertical direction of FIG. 15 is reduced.

Next, as shown in FIG. 16, the third semiconductor substrate 213 isjoined to the second semiconductor substrate 212. At this time, thesecond semiconductor substrate 212 is joined to the third semiconductorsubstrate 213 such that the multilayer wire layer 345 of the thirdsemiconductor substrate faces upward in FIG. 16.

In addition, as shown in FIG. 17, the first semiconductor substrate 211is thinned. In FIG. 17, the width of the first semiconductor substrate211 in the vertical direction of FIG. 17 is reduced.

Next, as shown in FIG. 18, the contact 312 and the contact 266 areformed. At this time, a hole is provided which reaches the multilayerwire layer 245 from the light receiving surface of the firstsemiconductor substrate 211, and a hole is provided which reaches thealuminum pad 280 of the multilayer wire layer 255 from the lightreceiving surface, thereby forming the contact 266. In addition, a holeis provided which reaches the aluminum pad 280 of the multilayer wirelayer 255 from the light receiving surface of the first semiconductorsubstrate 211, and a hole is provided which reaches the multilayer wirelayer 345 from the light receiving surface, thereby forming the contact312

In addition, as shown in FIG. 19, the pad hole 351 is formed so as toreach the aluminum pad 280 a from the rear surface side (light receivingsurface side) of the first semiconductor substrate 211.

In this way, the solid-state imaging device described with reference toFIG. 12 is manufactured. Thus, it is possible to block light caused byhot carriers by the multilayer wire layer 255. In addition, the aluminumpad 280 is disposed in the multilayer wire layer 255 including the sixwire layers, and thus it is easy to locate the aluminum pad 280 so as toblock light caused by hot carriers without restricting a shape of themetal wire 250. Further, since the aluminum pad 280 is provided in themultilayer wire layer 255 of the second semiconductor substrate 212, itis unnecessary to provide an ESD circuit in the first semiconductorsubstrate 211 (because an ESD circuit is preferably formed in the secondsemiconductor substrate), and thus it is possible to manufacture asolid-state imaging device at a low cost.

FIG. 20 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

In the configuration shown in FIG. 20, in the same manner as in the caseof FIG. 11, the multilayer wire layer 255 of the second semiconductorsubstrate faces the third semiconductor substrate 213 side (the lowerside of FIG. 20), and the first semiconductor substrate 211 is joined tothe second semiconductor substrate 212.

In addition, in the configuration shown in FIG. 20, in the same manneras in the case of FIG. 11, the contact 265 used for electricalconnection between the first semiconductor substrate 211 and the secondsemiconductor substrate 212 and the contact 311 used for electricalconnection between the second semiconductor substrate 212 and the thirdsemiconductor substrate 213 are provided. The contact 265 and thecontact 311 are respectively formed by a twin contact.

In addition, in the configuration shown in FIG. 20, unlike in the caseof FIG. 11, an insulating film layer 230 is formed between the firstsemiconductor substrate 211 and the second semiconductor substrate 212.Further, the aluminum pad 280 a is disposed in the insulating film layer230, and the aluminum pad 280 a is connected to a contact 313 which isconnected to the multilayer wire layer 255 of the second semiconductorsubstrate 212.

Furthermore, in the configuration shown in FIG. 20, the pad hole 351 isformed in the first semiconductor substrate 211 so as to reach thealuminum pad 280 a inside the insulating film layer 230 from the rearsurface side (light receiving surface side) of the first semiconductorsubstrate 211.

In a case of the configuration shown in FIG. 20, since the aluminum pad280 is provided in the insulating film layer 230, it is unnecessary toprovide an ESD circuit in the first semiconductor substrate 211 (becausean ESD circuit is preferably formed in the second semiconductorsubstrate), and thus it is possible to manufacture a solid-state imagingdevice at a low cost.

Next, a manufacturing process of the solid-state imaging device shown inFIG. 20 will be described.

First, as shown in FIG. 21, the first semiconductor substrate 211, thesecond semiconductor substrate 212, and the third semiconductorsubstrate 213 are prepared which are respectively provided with themultilayer wire layers. As shown in FIG. 21, the first semiconductorsubstrate 211 is provided with the multilayer wire layer 245, the secondsemiconductor substrate 212 is provided with the multilayer wire layer255, and the third semiconductor substrate 213 is provided with themultilayer wire layer 345.

In addition, as shown in FIG. 21, the aluminum pad 280 is not formed inthe multilayer wire layer 255 of the second semiconductor substrate 212.

Next, as shown in FIG. 22, the second semiconductor substrate 212 isjoined to the third semiconductor substrate 213. At this time, thesecond semiconductor substrate 212 is joined to the third semiconductorsubstrate 213 such that the multilayer wire layer 255 and the multilayerwire layer 345 face each other.

In addition, as shown in FIG. 23, the second semiconductor substrate 212is thinned. In FIG. 23, the width of the second semiconductor substrate212 in the vertical direction of FIG. 23 is reduced.

Next, as shown in FIG. 24, the contact 311 and the contact 313 areformed. At this time, a hole is provided which reaches the multilayerwire layer 345 from the upper surface of the second semiconductorsubstrate 212 in FIG. 24, and a hole is provided which reaches themultilayer wire layer 255 from the upper surface of the secondsemiconductor substrate 212 in FIG. 24, thereby forming the contact 311.In addition, a hole is provided which reaches the multilayer wire layer255 from the upper surface of the second semiconductor substrate 212 inFIG. 24, thereby forming the contact 313.

In addition, as shown in FIG. 25, the aluminum pad 280 a is formed, andthe insulating film layer 230 is formed. As shown in FIG. 25, thealuminum pad 280 a is formed so as to be connected to the upper end ofthe contact 313 in FIG. 25. In addition, the insulating film layer 230is formed around the aluminum pad 280 a in the upper surface of thesecond semiconductor substrate 212 in FIG. 25. Next, as shown in FIG.26, the first semiconductor substrate 211 is joined to the secondsemiconductor substrate 212 (more accurately, the insulating film layer230). At this time, the first semiconductor substrate 211 is joined tothe second semiconductor substrate 212 such that the multilayer wirelayer 245 comes into contact with the insulating film layer 230.

In addition, the first semiconductor substrate 211 is thinned. In FIG.26, the width of the first semiconductor substrate 211 in the verticaldirection of FIG. 26 is reduced.

In addition, as shown in FIG. 27, the pad hole 351 is formed so as toreach the aluminum pad 280 a from the rear surface side (light receivingsurface side) of the first semiconductor substrate 211. Successively, ahole is provided which reaches the multilayer wire layer 245 from thelight receiving surface of the first semiconductor substrate 211, and ahole is provided which reaches the contact 311 from the light receivingsurface, thereby forming the contact 265.

In this way, the solid-state imaging device described with reference toFIG. 20 is manufactured. Further, since the aluminum pad 280 is providedin the insulating film layer 230, it is unnecessary to provide an ESDcircuit in the first semiconductor substrate 211 (because an ESD circuitis preferably formed in the second semiconductor substrate), and thus itis possible to manufacture a solid-state imaging device at a low cost.

FIG. 28 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

In the configuration shown in FIG. 28, in the same manner as in the caseof FIG. 11, the pad hole 351 is formed in the first semiconductorsubstrate 211 so as to reach the aluminum pad 280 a from the rearsurface side (light receiving surface side) of the first semiconductorsubstrate 211. In addition, the aluminum pad 280 is formed in themultilayer wire layer 245 of the first semiconductor substrate 211.

In the configuration shown in FIG. 28, in the same manner as in the caseof FIG. 11, the multilayer wire layer 255 of the second semiconductorsubstrate faces the third semiconductor substrate 213 side (the lowerside of FIG. 28), and the first semiconductor substrate 211 is joined tothe second semiconductor substrate 212.

In addition, in the configuration shown in FIG. 28, in the same manneras in the case of FIG. 11, the contact 265 used for electricalconnection between the first semiconductor substrate 211 and the secondsemiconductor substrate 212 is provided. The contact 265 is formed by atwin contact.

In the configuration shown in FIG. 28, unlike in the case of FIG. 11,the contact 311 used for electrical connection between the secondsemiconductor substrate 212 and the third semiconductor substrate 213 isnot provided. On the other hand, the contact 314 and the contact 315used for electrical connection between the second semiconductorsubstrate 212 and the third semiconductor substrate 213 are provided.

Each of the contact 314 and the contact 315 is formed by providing athrough hole which penetrates through the second semiconductor substrate212 and reaches the multilayer wire layer 345 of the third semiconductorsubstrate 213 and embedding a conductor therein. In other words, each ofthe contact 314 and the contact 315 connects the multilayer wire layer255 of the second semiconductor substrate 212 to the multilayer wirelayer 345 of the third semiconductor substrate 213 by providing only asingle through hole.

In other words, each of the contact 314 and the contact 315 is formed bya shared contact.

In the configuration shown in FIG. 28, it is possible to simplifymanufacturing steps and to reduce the area occupying the substrate byusing the shared contact.

Although the description has been provided here of a case where theshared contact is used for electrical connection between the secondsemiconductor substrate 212 and the third semiconductor substrate 213,the shared contact may be used for electrical connection between thefirst semiconductor substrate 211 and the second semiconductor substrate212.

In addition, similarly, in the solid-state imaging device with theconfiguration described with reference to FIG. 11, 12 or 20, the sharedcontact may also be used for electrical connection between the firstsemiconductor substrate 211 and the second semiconductor substrate 212,or electrical connection between the second semiconductor substrate 212and the third semiconductor substrate 213.

In other words, in the configuration (FIG. 11) in which the aluminum pad280 is provided in the multilayer wire layer 245 of the firstsemiconductor substrate 211, the shared contact may be used forelectrical connections between the respective semiconductor substrates.In addition, in the configuration (FIG. 12) in which the aluminum pad280 is provided in the multilayer wire layer 255 of the secondsemiconductor substrate 212, the shared contact may be used forelectrical connections between the respective semiconductor substrates.Further, in the configuration (FIG. 20) in which the aluminum pad 280 isprovided in the insulating film layer 230, the shared contact may beused for electrical connections between the respective semiconductorsubstrates.

FIG. 29 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

In the configuration shown in FIG. 29, in the same manner as in the caseof FIG. 11, the pad hole 351 is formed in the first semiconductorsubstrate 211 so as to reach the aluminum pad 280 a from the rearsurface side (light receiving surface side) of the first semiconductorsubstrate 211. In addition, the aluminum pad 280 is formed in themultilayer wire layer 245 of the first semiconductor substrate 211.

In the configuration shown in FIG. 29, in the same manner as in the caseof FIG. 11, the multilayer wire layer 255 of the second semiconductorsubstrate faces the third semiconductor substrate 213 side (the lowerside of FIG. 29), and the first semiconductor substrate 211 is joined tothe second semiconductor substrate 212.

In addition, in the configuration shown in FIG. 29, a contact 267 usedfor an electrical connection between the second semiconductor substrate212 and the third semiconductor substrate 213 is provided. The contact267 is formed by a twin contact. Further, in the configuration shown inFIG. 29, a metal wire 250 a in the multilayer wire layer 255 of thesecond semiconductor substrate 212 is directly bonded to a metal wire340 a in the multilayer wire layer 345 of the third semiconductorsubstrate 213. Furthermore, a metal wire 250 b in the multilayer wirelayer 255 is directly bonded to a metal wire 340 b in the multilayerwire layer 345. Thus, the second semiconductor substrate 212 iselectrically connected to the third semiconductor substrate 213.

In other words, in a case of the configuration shown in FIG. 29, not acontact but direct bonding is used for electrical connection between thesecond semiconductor substrate 212 and the third semiconductor substrate213. Therefore, it is possible to simplify manufacturing steps and toreduce the area occupying the substrate.

In addition, the direct bonding is disclosed in detail in, for example,Japanese Unexamined Patent Application Publication No. 2013-033900 whichis hereby incorporated herein by reference in its entirety for all thatit teaches and for all purposes.

Next, a manufacturing process of the solid-state imaging device shown inFIG. 29 will be described.

First, as shown in FIG. 30, the first semiconductor substrate 211, thesecond semiconductor substrate 212, and the third semiconductorsubstrate 213 are prepared which are respectively provided with themultilayer wire layers. As shown in FIG. 30, the first semiconductorsubstrate 211 is provided with the multilayer wire layer 245, the secondsemiconductor substrate 212 is provided with the multilayer wire layer255, and the third semiconductor substrate 213 is provided with themultilayer wire layer 345.

In addition, as shown in FIG. 30, the aluminum pad 280 is formed in themultilayer wire layer 245 of the first semiconductor substrate 211.Further, the metal wire 250 and the metal wire 250 b are formed in themultilayer wire layer 255 of the second semiconductor substrate, and themetal wire 340 a and the metal wire 340 b are formed in the multilayerwire layer 345 of the third semiconductor substrate.

Next, as shown in FIG. 31, the second semiconductor substrate 212 isjoined to the third semiconductor substrate 213. At this time, thesecond semiconductor substrate 212 is joined to the third semiconductorsubstrate 213 such that the multilayer wire layer 255 and the multilayerwire layer 345 face each other. In addition, the metal wire 250 a isdirectly bonded to the metal wire 340 a, and the metal wire 250 b isdirectly bonded to the metal wire 340 b.

In addition, the second semiconductor substrate 212 is thinned. In FIG.31, the width of the second semiconductor substrate 212 in the verticaldirection of FIG. 31 is reduced.

Next, as shown in FIG. 32, the first semiconductor substrate 211 isjoined to the second semiconductor substrate 212. At this time, themultilayer wire layer 255 of the second semiconductor substrate facesthe third semiconductor substrate 213 side (the lower side of FIG. 32),and the first semiconductor substrate 211 is joined to the secondsemiconductor substrate 212.

In addition, the first semiconductor substrate 211 is thinned. In FIG.32, the width of the first semiconductor substrate 211 in the verticaldirection of FIG. 32 is reduced.

Next, the contact 267 is formed as shown in FIG. 33. At this time, ahole is provided which reaches the multilayer wire layer 245 from thelight receiving surface of the first semiconductor substrate 211, and ahole is provided which reaches the multilayer wire layer 255 from thelight receiving surface, thereby forming the contact 267.

In addition, as shown in FIG. 34, the pad hole 351 is formed so as toreach the aluminum pad 280 a from the rear surface side (light receivingsurface side) of the first semiconductor substrate 211.

In this way, the solid-state imaging device described with reference toFIG. 29 is manufactured. Since not a contact but direction bonding isused for electrical connection between the second semiconductorsubstrate 212 and the third semiconductor substrate 213, it is possibleto simplify manufacturing steps and to reduce the area occupying thesubstrate.

Although the description has been provided here of a case where thedirect bonding is used as an electrical connection between the secondsemiconductor substrate 212 and the third semiconductor substrate 213,the direct bonding may be used as an electrical connection between thefirst semiconductor substrate 211 and the second semiconductor substrate212.

Similarly, in the solid-state imaging device with the configurationdescribed with reference to FIG. 11, 12 or 20, the direct bonding mayalso be used as an electrical connection between the first semiconductorsubstrate 211 and the second semiconductor substrate 212, or as anelectrical connection between the second semiconductor substrate 212 andthe third semiconductor substrate 213.

In other words, in the configuration (FIG. 11) in which the aluminum pad280 is provided in the multilayer wire layer 245 of the firstsemiconductor substrate 211, the direct bonding may be used as anelectrical connection between the respective semiconductor substrates.In addition, in the configuration (FIG. 12) in which the aluminum pad280 is provided in the multilayer wire layer 255 of the secondsemiconductor substrate 212, the direct bonding may be used as anelectrical connection between the respective semiconductor substrates.Further, in the configuration (FIG. 20) in which the aluminum pad 280 isprovided in the insulating film layer 230, the direct bonding may beused as an electrical connection between the respective semiconductorsubstrates.

FIG. 35 is a schematic diagram of the cross-sectional view illustratingthe configuration according to still another embodiment of the pixelportion of the solid-state imaging device to which the presenttechnology is applied.

In the configuration shown in FIG. 35, unlike in the case of FIG. 29, acontact 268 and a contact 316 used as an electrical connection betweenthe first semiconductor substrate 211 and the second semiconductorsubstrate 212 are provided. In other words, in a case of theconfiguration shown in FIG. 35, the lower left end of the contact 268 inFIG. 35 is connected to the upper end of the contact 316 in FIG. 35, andthereby the first semiconductor substrate 211 is electrically connectedto the second semiconductor substrate 212. In addition, the contact 268is formed by a twin contact.

In the configuration shown in FIG. 35, it is unnecessary to provide ahole which reaches the multilayer wire layer 255 from the lightreceiving surface, for example, unlike in forming the contact 267 ofFIG. 29. For this reason, it is possible to more simply form a contact.

A configuration of the other elements in FIG. 35 is the same as in thecase of FIG. 29, and detailed description thereof will be made.

Next, a manufacturing process of the solid-state imaging device shown inFIG. 35 will be described.

First, as shown in FIG. 36, the first semiconductor substrate 211, thesecond semiconductor substrate 212, and the third semiconductorsubstrate 213 are prepared which are respectively provided with themultilayer wire layers. As shown in FIG. 36, the first semiconductorsubstrate 211 is provided with the multilayer wire layer 245, the secondsemiconductor substrate 212 is provided with the multilayer wire layer255, and the third semiconductor substrate 213 is provided with themultilayer wire layer 345.

In addition, as shown in FIG. 36, the aluminum pad 280 is formed in themultilayer wire layer 245 of the first semiconductor substrate 211.Further, the metal wire 250 a and the metal wire 250 b are formed in themultilayer wire layer 255 of the second semiconductor substrate, and themetal wire 340 a and the metal wire 340 b are formed in the multilayerwire layer 345 of the third semiconductor substrate.

Next, as shown in FIG. 37, the second semiconductor substrate 212 isjoined to the third semiconductor substrate 213. At this time, thesecond semiconductor substrate 212 is joined to the third semiconductorsubstrate 213 such that the multilayer wire layer 255 and the multilayerwire layer 345 face each other. In addition, the metal wire 250 a isdirectly bonded to the metal wire 340 a, and the metal wire 250 b isdirectly bonded to the metal wire 340 b.

In addition, the second semiconductor substrate 212 is thinned. In FIG.37, the width of the second semiconductor substrate 212 in the verticaldirection of FIG. 31 is reduced.

In addition, as shown in FIG. 38, the contact 316 is formed. At thistime, a hole is provided which reaches the multilayer wire layer 255from the upper surface of the second semiconductor substrate 212 in FIG.38 so as to form the contact 316.

Next, as shown in FIG. 39, the first semiconductor substrate 211 isjoined to the second semiconductor substrate 212. At this time, thefirst semiconductor substrate 211 is joined to the second semiconductorsubstrate 212 such that the rear surface of the first semiconductorsubstrate 211 becomes a light receiving surface.

In addition, the first semiconductor substrate 211 is thinned. In FIG.39, the width of the first semiconductor substrate 211 in the verticaldirection of FIG. 39 is reduced.

Further, a hole is provided which reaches the upper surface of thesecond semiconductor substrate in FIG. 39 from the light receivingsurface of the first semiconductor substrate 211, and a hole is providedwhich reaches the aluminum pad 280 of the multilayer wire layer 245 fromthe light receiving surface, thereby forming the contact 268.

In addition, as shown in FIG. 40, the pad hole 351 is formed so as toreach the aluminum pad 280 a from the light receiving surface of thefirst semiconductor substrate 211.

In this way, the solid-state imaging device described with reference toFIG. 35 is manufactured. In the configuration shown in FIG. 35, asdescribed above, the contact 268 and the contact 316 are used as anelectrical connection between the first semiconductor substrate 211 andthe second semiconductor substrate 212. In other words, a conductorforming the contact 268 is bonded to a conductor forming the contact 316at the bonding surface between the first semiconductor substrate 211 andthe second semiconductor substrate 212. As above, in a case of theconfiguration shown in FIG. 35, a part of the twin contact for anelectrical connection between the first semiconductor substrate 211 andthe second semiconductor substrate 212 is formed in two divided steps.

In this way, it is unnecessary to provide a deep hole which reaches themultilayer wire layer 255 from the light receiving surface, for example,unlike in forming the contact 267 of FIG. 29. For this reason, it ispossible to more simply form a contact.

Although the description has been provided here of a case where a partof the twin contact used for an electrical connection between the firstsemiconductor substrate 211 and the second semiconductor substrate 212is formed in two divided steps, a part of a twin contact used for anelectrical connection between the second semiconductor substrate 212 andthe third semiconductor substrate 213 may be formed in two dividedsteps.

In addition, similarly, in the solid-state imaging device with theconfiguration described with reference to FIG. 11, 12 or 20, a part of atwin contact, used for an electrical connection between the firstsemiconductor substrate 211 and the second semiconductor substrate 212,or electrical connection between the second semiconductor substrate 212and the third semiconductor substrate 213, may be formed in two dividedsteps.

In other words, in the configuration (FIG. 11) in which the aluminum pad280 is provided in the multilayer wire layer 245 of the firstsemiconductor substrate 211, a part of a twin contact used for anelectrical connected between the respective semiconductor substrates maybe formed in two divided steps. In addition, in the configuration (FIG.12) in which the aluminum pad 280 is provided in the multilayer wirelayer 255 of the second semiconductor substrate 212, a part of a twincontact used for an electrical connected between the respectivesemiconductor substrates may be formed in two divided steps. Further, inthe configuration (FIG. 20) in which the aluminum pad 280 is provided inthe insulating film layer 230, a part of a twin contact used for anelectrical connected between the respective semiconductor substrates maybe formed in two divided steps.

As described with reference to FIGS. 11 to 40, in the solid-stateimaging device to which the present technology is applied, the aluminumpad 280 may be provided in the multilayer wire layer 245 of the firstsemiconductor substrate 211, the aluminum pad 280 may be provided in themultilayer wire layer 255 of the second semiconductor substrate 212, andthe aluminum pad 280 may be provided in the insulating film layer 230.In addition, as a form of electrical connection between the respectivesemiconductor substrates, a twin contact, a shared contact, directbonding, and a configuration in which a part of a twin contact is formedin two divided steps may be employed.

In other words, combinations as shown in FIG. 41 may be employed asembodiments of the solid-state imaging device to which the presenttechnology is applied.

In addition, in the above-described embodiments, the embodiments of thesolid-state imaging device to which the present technology is appliedhave been described based on a three-layer stacked structure. However,the solid-state imaging device to which the present technology isapplied may employ, for example, a four-layer structure in which a firstsemiconductor substrate, a second semiconductor substrate, a thirdsemiconductor substrate, and a fourth semiconductor substrate arestacked.

FIG. 42 shows an example of a case where the solid-state imaging deviceto which the present technology is applied employs the four-layerstructure. FIG. 42 is a schematic diagram of a cross-sectional viewillustrating a configuration according to still another embodiment ofthe pixel portion of the solid-state imaging device to which the presenttechnology is applied.

In the example shown in FIG. 42, a four-layer structure is employed inwhich a first semiconductor substrate 211, a second semiconductorsubstrate 212, a third semiconductor substrate 213, and a fourthsemiconductor substrate 214 are stacked.

In addition, similarly, the solid-state imaging device to which thepresent technology is applied may employ a structure of five or morelayers.

FIG. 43 is a block diagram illustrating a configuration example of acamera apparatus which is an electronic apparatus to which the presenttechnology is applied.

A camera apparatus 600 in FIG. 43 includes an optical unit 601 includinga lens group and the like, a solid-state imaging device (imaging device)602 which employs the above-described respective configurations of thepixels 402, and a DSP circuit 603 which is a camera signal processingcircuit. In addition, the camera apparatus 600 includes a frame memory604, a display unit 605, a recording unit 606, an operation unit 607,and a power supply unit 608. The DSP circuit 603, the frame memory 604,the display unit 605, the recording unit 606, the operation unit 607,and the power supply unit 608 are connected to each other via a bus line609.

The optical unit 601 receives incident light (image light) from asubject so as to be imaged on an imaging surface of the solid-stateimaging device 602. The solid-state imaging device 602 converts a lightamount of the incident light which is imaged on the imaging surface bythe optical unit 601 into an electric signal in the unit of a pixel andoutputs the electric signal as a pixel signal. The solid-state imagingdevice related to the above-described embodiments may be used as thesolid-state imaging device 602.

The display unit 605 includes, for example, a panel type display devicesuch as a liquid crystal panel or an organic electroluminescence (EL)panel, and displays moving images or still images captured by thesolid-state imaging device 602. The recording unit 606 records movingimages or still images captured by the solid-state imaging device 602 ona recording medium such as a video tape or a digital versatile disk(DVD).

The operation unit 607 issues operation commands for various functionsof the camera apparatus 600 in response to an operation by a user. Thepower supply unit 608 appropriately supplies a variety of power which isoperation power of the DSP circuit 603, the frame memory 604, thedisplay unit 605, the recording unit 606, and the operation unit 607, tothe supply targets.

In addition, the present technology is not limited to being applied to asolid-state imaging device which detects a distribution of an incidentlight amount of visible light so as to capture an image, and isgenerally applicable to a solid-state imaging device which detects adistribution of an incidence amount of infrared rays, X rays, particles,or the like so as to capture an image, or a solid-state imaging device(physical quantity distribution detection device) such as a fingerprintdetection sensor which detects distributions of the other physicalquantities such as a pressure or a capacitance so as to capture an imagein a broad sense.

In addition, embodiments of the present technology are not limited tothe above-described embodiments and may have various modificationswithin the scope without departing from the spirit of the presenttechnology.

Further, the present technology may have the following configurations.

(1)

A solid-state imaging device including a first semiconductor substratethat includes a sensor circuit provided with a photoelectric conversionportion; and a second semiconductor substrate and a third semiconductorsubstrate that respectively include circuits different from the sensorcircuit, wherein the first semiconductor substrate is located in theuppermost layer, and the first semiconductor substrate, the secondsemiconductor substrate, and the third semiconductor substrate arestacked in three layers, and wherein an electrode metal element formingan electrode for external connection is disposed in the firstsemiconductor substrate.

(2)

The solid-state imaging device according to (1), wherein the sensorcircuit of the first semiconductor substrate is of a rear surfaceirradiation type, and wherein a hole exposing the electrode metalelement is opened from a light receiving surface side of the firstsemiconductor substrate.

(3)

The solid-state imaging device according to (1) or (2), wherein thesecond semiconductor substrate or the third semiconductor substrateincludes a logical circuit or a memory circuit, and wherein the logicalcircuit or the memory circuit is operated based on input and output ofsignals to and from an external device.

(4)

The solid-state imaging device according to any one of (1) to (3),wherein a light blocking mechanism which blocks light incident to thephotoelectric conversion portion from an opposite side to a lightreceiving surface of the first semiconductor substrate is provided in atleast one of the first semiconductor substrate and the secondsemiconductor substrate.

(5)

The solid-state imaging device according to (4), wherein the lightblocking mechanism is formed by the electrode metal element.

(6)

The solid-state imaging device according to (4), wherein a wire metalelement used for a wire of the second semiconductor substrate isdisposed in the second semiconductor substrate, and wherein the lightblocking mechanism is formed by the electrode metal element and the wiremetal element.

(7)

The solid-state imaging device according to (4), wherein the lightblocking mechanism is formed by a light blocking body disposed in thesecond semiconductor substrate.

(8)

The solid-state imaging device according to (1), wherein a wire metalelement used for a wire of the first semiconductor substrate is furtherdisposed in the first semiconductor substrate, and wherein the electrodemetal element is disposed at a position closer to an adhesive surfacewith the second semiconductor substrate than the wire metal element.

(9)

The solid-state imaging device according to any one of (1) to (8),wherein a contact, which penetrates through the first semiconductorsubstrate or the second semiconductor substrate and reaches a metal wirelayer of the second semiconductor substrate or the third semiconductorsubstrate, a part of which reaches a wire of a wire metal layer of thefirst semiconductor substrate or the second semiconductor substrate, isused for electrical connection between the first semiconductor substrateand the second semiconductor substrate or electrical connection betweenthe second semiconductor substrate and the third semiconductorsubstrate.

(10)

The solid-state imaging device according to any one of (1) to (8),wherein a part of a contact used for electrical connection between thefirst semiconductor substrate and the second semiconductor substrate orelectrical connection between the second semiconductor substrate and thethird semiconductor substrate is formed by connecting conductors to eachother at a bonding surface between the first semiconductor substrate andthe second semiconductor substrate or a bonding surface between thesecond semiconductor substrate and the third semiconductor substrate.

(11)

The solid-state imaging device according to any one of (1) to (8),wherein wires exposed to a bonding surface between the firstsemiconductor substrate or the second semiconductor substrate and thesecond semiconductor substrate or the third semiconductor substrate arebonded to each other such that the first semiconductor substrate iselectrically connected to the second semiconductor substrate.

(12)

The solid-state imaging device according to (1), wherein the firstsemiconductor substrate and the second semiconductor substrate arestacked such that a metal wire layer of the second semiconductorsubstrate comes into contact with the first semiconductor substrate, andwherein an electrode metal element forming an electrode for externalconnection is disposed inside a metal wire layer of the secondsemiconductor substrate.

(13)

The solid-state imaging device according to (1), wherein an insulatingfilm layer is formed between the first semiconductor substrate and thesecond semiconductor substrate, wherein the first semiconductorsubstrate and the second semiconductor substrate are stacked such that ametal wire layer of the second semiconductor substrate comes intocontact with the insulating film layer, and wherein an electrode metalelement forming an electrode for external connection is disposed insidethe insulating film layer.

(14)

An electronic apparatus including a solid-state imaging device having afirst semiconductor substrate that includes a sensor circuit providedwith a photoelectric conversion portion; and a second semiconductorsubstrate and a third semiconductor substrate that respectively includecircuits different from the sensor circuit, wherein the firstsemiconductor substrate is located in the uppermost layer, and the firstsemiconductor substrate, the second semiconductor substrate, and thethird semiconductor substrate are stacked in three layers, and whereinan electrode metal element forming an electrode for external connectionis disposed in the first semiconductor substrate.

<1>

A semiconductor device comprising:

a first semiconductor section including a first wiring layer at one sidethereof, the first semiconductor section further including a photodiode;

a second semiconductor section including a second wiring layer at oneside thereof, the first and second semiconductor sections being securedtogether;

a third semiconductor section including a third wiring layer at one sidethereof, the second and the third semiconductor sections being securedtogether such the first semiconductor section, second semiconductorsection, and the third semiconductor section are stacked together; and

a first conductive material electrically connecting at least two of (i)the first wiring layer, (ii) the second wiring layer, and (iii) thethird wiring layer such that the electrically connected wiring layersare in electrical communication.

<2>

The semiconductor device of <1>, wherein the first semiconductorsection, the second semiconductor section, and the third semiconductorsection are stacked together in a manner such that the first wiringlayer faces the second wiring layer or the second wiring layer faces thethird wiring layer.

<3>

The semiconductor device of <2>, further comprising: a second conductivematerial electrically connecting at least two of (i) the first wiringlayer, (ii) the second wiring layer, and (iii) the third wiring layersuch that the electrically connected wiring layers are in electricalcommunication.

<4>

The semiconductor device of <3>, wherein at least one wiring layerelectrically connected by the second conductive material is differentthan the wiring layers electrically connected by the first conductivematerial.

<5>

The semiconductor device of <3>or <4>, wherein at least one of the firstconductive material and the second conductive material comprises twothrough holes which penetrate through at least one of the firstsemiconductor section and the second semiconductor section in a verticaldirection; and wherein a first through hole of the first conductivematerial electrically connects to a wiring layer that is different thana wiring layer electrically connected by a second of the two throughholes.

<6>

The semiconductor device of <3>or <4>wherein at least one of the firstconductive material and the second conductive material comprises asingle through hole which penetrates through at least one of the firstsemiconductor section and the second semiconductor section in a verticaldirection such that the at least one of the first conductive materialand the second conductive material electrically contact at least twowiring layers.

<7>

The semiconductor device of any one of <1>to <6>, wherein a metal wireof at least one of (i) the first wiring layer, (ii) the second wiringlayer, and (ii) the third wiring layer is directly bonded to a metalwire in another wiring layer.

<8>

The semiconductor device of <7>, wherein at least one of the wiringlayers having a metal wire directly bonded is different than the wiringlayers electrically connected by the first conductive material.

<9>

The semiconductor device of any one of <1>to <8>, further comprising apad electrode for external connection.

<10>

The semiconductor device of <9>, wherein the pad is disposed such thatlight is blocked from one or more transistors residing in the secondsemiconductor section.

<11>

The semiconductor device of any one of <1>to <10>, wherein the firstsemiconductor section comprises a sensor circuit, at least one of thesecond semiconductor section and the third semiconductor sectioncomprises a logical circuit, and at least one of the secondsemiconductor section and the third semiconductor section comprises amemory circuit.

<12>

A backside illumination type solid-state imaging device comprising:

a first semiconductor section including a first wiring layer at one sidethereof, the first semiconductor section further including a circuitregion and a pixel region;

a second semiconductor section including a second wiring layer at oneside thereof, the first and second semiconductor sections being securedtogether;

a third semiconductor section including a third wiring layer at one sidethereof, the second and the third semiconductor sections being securedtogether such the first semiconductor section, second semiconductorsection, and the third semiconductor section are stacked together; and

a first conductive material electrically connecting at least two of (i)the first wiring layer, (ii) the second wiring layer, and (iii) thethird wiring layer such that the electrically connected wiring layersare in electrical communication.

<13>

The solid-state imaging device of <12>, wherein the first semiconductorsection, the second semiconductor section, and the third semiconductorsection are stacked together in a manner such that the first wiringlayer faces the second wiring layer or the second wiring layer faces thethird wiring layer.

<14>

The solid-state imaging device of <13>, further comprising: a secondconductive material electrically connecting at least two of (i) thefirst wiring layer, (ii) the second wiring layer, and (iii) the thirdwiring layer such that the electrically connected wiring layers are inelectrical communication.

<15>

The solid-state imaging device of <14>, wherein at least one of thefirst conductive material and the second conductive material comprises asingle through hole which penetrates through at least one of the firstsemiconductor section and the second semiconductor section in a verticaldirection such that the at least one of the first conductive materialand the second conductive material electrically contact at least twowiring layers.

<16>

The solid-state imaging device of any one of <12>to <15>, wherein ametal wire of at least one of (i) the first wiring layer, (ii) thesecond wiring layer, and (ii) the third wiring layer is directly bondedto a metal wire in another wiring layer.

<17>

The solid-state imaging device of any one of <12>to <16>, wherein atleast one of the wiring layers having a metal wire directly bonded isdifferent than the wiring layers electrically connected by the firstconductive material.

<18>

The solid-state imaging device of any one of <12>to <17>, furthercomprising a pad electrode for external connection, wherein the pad isdisposed below the pixel region such that light is blocked from one ormore transistors residing in the second semiconductor section.

<19>

The solid-state imaging device of any one of <12>to <18>, furthercomprising an interlayer insulating film disposed between at least twoof the semiconductor sections.

<20>

The solid-state imaging device of any one of <12>to <19>, wherein thefirst semiconductor section comprises a sensor circuit, at least one ofthe second semiconductor section and the third semiconductor sectioncomprises a logical circuit, and at least one of the secondsemiconductor section and the third semiconductor section comprises amemory circuit.

<21>

An electronic apparatus including:

an optical unit; and

-   -   (a) a solid-state imaging device including: a first        semiconductor section including a first wiring layer at one side        thereof, the first semiconductor section further including a        circuit region and a pixel region;        -   a second semiconductor section including a second wiring            layer at one side thereof, the first and second            semiconductor sections being secured together;    -   (b) a third semiconductor section including a third wiring layer        at one side thereof, the second and the third semiconductor        sections being secured together such the first semiconductor        section, second semiconductor section, and the third        semiconductor section are stacked together; and    -   (c) a first conductive material electrically connecting at least        two of (i) the first wiring layer, (ii) the second wiring layer,        and (iii) the third wiring layer such that the electrically        connected wiring layers are in electrical communication.

<22>

The electronic apparatus of <21>, wherein the first semiconductorsection, the second semiconductor section, and the third semiconductorsection are stacked together in a manner such that the first wiringlayer faces the second wiring layer or the second wiring layer faces thethird wiring layer.

<23>

The electronic apparatus of <22>, further comprising: a secondconductive material electrically connecting at least two of (i) thefirst wiring layer, (ii) the second wiring layer, and (iii) the thirdwiring layer such that the electrically connected wiring layers are inelectrical communication, wherein at least one wiring layer electricallyconnected by the second conductive material is different than the wiringlayers electrically connected by the first conductive material.

<24>

The electronic apparatus of <23>, wherein at least one of the firstconductive material and the second conductive material comprises twothrough holes which penetrate through at least one of the firstsemiconductor section and the second semiconductor section in a verticaldirection; and wherein a first through hole of the first conductivematerial electrically connects to a wiring layer that is different thana wiring layer electrically connected by a second of the two throughholes.

<25>

The electronic apparatus of <23>, wherein at least one of the firstconductive material and the second conductive material comprises asingle through hole which penetrates through at least one of the firstsemiconductor section and the second semiconductor section in a verticaldirection such that the at least one of the first conductive materialand the second conductive material electrically contact at least twowiring layers.

<26>

The electronic apparatus of <23>, wherein a metal wire of at least oneof (i) the first wiring layer, (ii) the second wiring layer, and (ii)the third wiring layer is directly bonded to a metal wire in anotherwiring layer, and wherein at least one of the wiring layers having ametal wire directly bonded is different than the wiring layerselectrically connected by the first conductive material.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

REFERENCE SIGNS LIST

211 First semiconductor substrate

212 Second semiconductor substrate

213 Third semiconductor substrate

230 Insulating film layer

234 Photodiode

240 Copper wire

245 Multilayer wire layer

250 Copper wire

255 Multilayer wire layer

265 Contact

266 Contact

267 Contact

280 Aluminum pad

311 Contact

312 Contact

313 Contact

320 Aluminum pad

330 Aluminum pad

340 Copper wire

345 Multilayer wire layer

351 Pad hole

360 Light blocking body

370 Copper wire

401 Solid-state imaging device

402 Pixel

600 Camera apparatus

602 Solid-state imaging device

What is claimed:
 1. An imaging device, comprising: a first semiconductorsection including a first wiring layer at a first side thereof, thefirst semiconductor section including a plurality of photodiodes at asecond side opposite to the first side of the first semiconductorsection and at least one of a transfer transistor, a reset transistor,and an amplification transistor; a second semiconductor sectionincluding a second wiring layer at a first side thereof and a pluralityof transistors, wherein the first and second semiconductor sections aresecured together such that the first side of the first semiconductorsection and the first side of the second semiconductor section arefacing each other; and a third semiconductor section including a thirdwiring layer and a plurality of transistors, wherein a second side ofthe second semiconductor substrate opposite to the first side of thesecond semiconductor section and a side of the third semiconductorsection are facing each other, wherein the first semiconductor sectionand the second semiconductor section are electrically connected to oneanother via a first conductor, wherein the second semiconductor sectionand the third semiconductor section are electrically connected to oneanother via a second conductor, and wherein an electrode for externalconnection is formed in the first semiconductor section.
 2. The imagingdevice according to claim 1, wherein the first conductor is connected toa wiring in the first semiconductor section and a wiring in the secondsemiconductor section.
 3. The imaging device according to claim 2,further comprising a pad in the wiring in the second semiconductorsection, wherein the first conductor is connected to the pad.
 4. Theimaging device according to claim 1, wherein the first conductor isdisposed in a first section other than a pixel section including theplurality of photodiodes.
 5. The imaging device according to the claim1, wherein the second conductor is connected to a wiring in the secondsemiconductor section and a wiring of the third semiconductor section.6. The imaging device according to the claim 1, wherein the secondsemiconductor substrate includes a logic circuit.
 7. The imaging deviceaccording to the claim 1, wherein the third semiconductor substrateincludes a memory circuit.
 8. An imaging device, comprising: a firstsemiconductor section including a first wiring layer at a first sidethereof, the first semiconductor section including a plurality ofphotodiodes at a second side opposite to the first side of the firstsemiconductor section and at least one of a transfer transistor, a resettransistor, and an amplification transistor; a second semiconductorsection including a second wiring layer at a first side thereof and aplurality of transistors, wherein the first and second semiconductorsections are secured together such that the first side of the firstsemiconductor section and the first side of the second semiconductorsection are facing each other; and a third semiconductor sectionincluding a third wiring layer at a first side thereof and a pluralityof transistors, wherein a second side of the second semiconductorsubstrate opposite to the first side of the second semiconductor sectionand the first side of the third semiconductor section are facing eachother, wherein the first semiconductor section and the secondsemiconductor section are electrically connected one another via a firstconductor, wherein the second semiconductor section and the thirdsemiconductor section are electrically connected one another via asecond conductor, and wherein an electrode for external connection isformed in the first semiconductor section.
 9. The imaging deviceaccording to claim 8, wherein the first conductor is connected to awiring in the first semiconductor section and a wiring in the secondsemiconductor section.
 10. The imaging device according to claim 9,further comprising a pad in the wiring in the second semiconductorsection, wherein the first conductor is connected to the pad.
 11. Theimaging device according to claim 8, wherein the first conductor isdisposed in a first section other than a pixel section including theplurality of photodiodes.
 12. The imaging device according to the claim8, wherein the second conductor is connected to a wiring in the secondsemiconductor section and a wiring of the third semiconductor section.13. The imaging device according to the claim 8, wherein the secondsemiconductor substrate includes a logic circuit.
 14. The imaging deviceaccording to the claim 8, wherein the third semiconductor substrateincludes a memory circuit.